Context transfers and multi-band operation for wireless networks

ABSTRACT

Various example embodiments are disclosed relating wireless networks and relating to context transfers and multi-band operation in wireless networks. In an example embodiment, a multi-band scheduler may be provided for use in a wireless node. The multi-band scheduler may be configured to: receive one or more data units of a flow; assign each received data unit of the flow to a first frequency band of a plurality of frequency bands; determine a band transfer condition for the flow; and perform a context transfer from the first frequency band to a second frequency band for the flow based on the determined band transfer condition.

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims priority under 35 U.S.C. §119(e) to U.S.Provisional Patent Application No. 60/938,018, filed on May 15, 2007.U.S. Provisional Patent Application No. 60/938,018 is incorporated byreference herein in its entirety.

BACKGROUND

Wireless networks have been developed that operate in differentfrequency bands, e.g., 900 MHz, 1800 MHz, 1900 MHz, 2.0 MHz, 3.5 MHz,and others. These are just a few examples of wireless frequency bandsthat may be used or are available for usage. Each frequency bandtypically includes a number of channels which may be assigned to usersor mobile terminals. Each channel may sometimes include a number ofsub-channels, e.g., multiple subcarriers and/or time slots. Multi-bandcellular devices are capable of transmitting or receiving on one ofseveral bands, e.g., depending on the available wireless service in anarea. Some Wireless Local Area Network (WLAN) devices, such as accesspoints and user devices, may also be multi-mode or multi-band, havingthe ability to operate in one of several modes or frequency bands, whichmay be associated with different standards. A number of differentwireless standards have been developed, such as the IEEE (The Instituteof Electrical and Electronics Engineers) 802.11 family ofspecifications, e.g., IEEE 802.11b, 802.11a, 802.11g, wirelessspecifications related to WiMAX or IEEE 802.16, specifications relatedto cellular communications, such as GSM (Global System for MobileCommunications), and many others.

However, multi-band operation is typically quite limited in suchdevices. There is a need for techniques that may provide improved usageof multiple frequency bands in wireless networks.

SUMMARY

Various example embodiments are disclosed relating to wireless networks,and relating to context transfers and multi-band operation in wirelessnetworks.

According to an example embodiment, a method may include transmitting,from a wireless node, a first data unit via a first channel of a firstfrequency band of a plurality of frequency bands, selecting a secondfrequency band of the plurality of frequency bands, performing a contexttransfer at the wireless node from the first frequency band to thesecond frequency band, and transmitting, from the wireless node, asecond data unit via a second channel of the second frequency band.

In another example embodiment, an apparatus may include a wirelesstransceiver, a controller or processor, memory, and a multi-bandscheduler. The apparatus may be configured to transmit, from a wirelessnode, a first data unit via a first channel of a first frequency band ofa plurality of frequency bands; select a second frequency band of theplurality of frequency bands; perform a context transfer at the wirelessnode from the first frequency band to the second frequency band; andtransmit, from the wireless node, a second data unit via a secondchannel of the second frequency band.

In another example embodiment, a method may include transmitting one ormore data units of a group of data units via a first channel of a firstfrequency band in a wireless network using an ARQ process; re-assigningthe group of data units and associated control data from the firstfrequency band to a second frequency band; and continuing to transmitthe group of data units via a second channel of the second frequencyband using the ARQ process.

In an example embodiment, an apparatus may include a wirelesstransceiver, and a multi-band scheduler. The apparatus may be configuredto: transmit one or more data units of a group of data units via a firstchannel of a first frequency band in a wireless network using an ARQprocess; re-assign the group of data units and associated control datafrom the first frequency band to a second frequency band; and continueto transmit the group of data units via a second channel of the secondfrequency band using the ARQ process.

In another example embodiment a method may include transmitting a dataunit via a first channel of a first frequency band in a wireless networkusing an ARQ process; failing to receive an indication that the dataunit was successfully received; performing a context transfer from thefirst frequency band to a second frequency band, including re-assigningone or more data units, including the transmitted data unit, and atleast some associated control data of the one or more data units, fromthe first frequency band to the second frequency band; andretransmitting the transmitted data unit using a second channel of thesecond frequency band according to the ARQ process.

In another example embodiment, an apparatus may include a wirelesstransceiver, and a controller. The apparatus (or the controller) may beconfigured to: transmit a data unit via a first channel of a firstfrequency band in a wireless network using an ARQ process; fail toreceive an indication that the data unit was successfully received;perform a context transfer from the first frequency band to a secondfrequency band, including re-assigning one or more data units, includingthe transmitted data unit, and at least some associated control data ofthe one or more data units, from the first frequency band to the secondfrequency band; and retransmit the transmitted data unit using a secondchannel of the second frequency band according to the ARQ process.

In another example embodiment, a method may include transmitting datavia a first channel on a first frequency band of a plurality offrequency bands in a wireless network; detecting a condition relating tothe first frequency band; reassigning (or transferring) at least somecontrol data relating to the first frequency band to a second frequencyband of the plurality of frequency bands; transferring data stored indata transmission queues associated with the first frequency band todata transmission queues associated with the second frequency band; andtransmitting the transferred data via the second frequency band.

According to another example embodiment, an apparatus may include awireless transceiver, and a controller. The apparatus (or thecontroller) may be configured to: transmit data via a first channel on afirst frequency band of a plurality of frequency bands in a wirelessnetwork; detect a condition relating to the first frequency band;reassign at least some control data relating to the first frequency bandto a second frequency band of the plurality of frequency bands; transferdata stored in data transmission queues associated with the firstfrequency band to data transmission queues associated with the secondfrequency band; and transmit the transferred data via the secondfrequency band.

According to another example embodiment, a method may include receivingone or more data units of a flow at a wireless node; assigning eachreceived data unit of the flow to a first frequency band of a pluralityof frequency bands; determining a band transfer condition for the flow;and performing a context transfer from the first frequency band to asecond frequency band for the flow based on the determined band transfercondition.

In another example embodiment, a method may include receiving one ormore data units of a first flow at a wireless node; assigning eachreceived data unit of the first flow to a first frequency band of aplurality of frequency bands; receiving one or more data units of asecond flow at a wireless node; assigning each received data unit of thesecond flow to a second frequency band of the plurality of frequencybands; determining a band transfer condition for the first flow; andperforming a context transfer from the first frequency band to thesecond frequency band for the first flow based on the determined bandtransfer condition.

In another example embodiment, a multi-band scheduler may be providedfor use in a wireless node. The multi-band scheduler may be configuredto: receive one or more data units of a flow; assign each received dataunit of the flow to a first frequency band of a plurality of frequencybands; determine a band transfer condition for the flow; and perform acontext transfer from the first frequency band to a second frequencyband for the flow based on the determined band transfer condition.

In yet another example embodiment, an apparatus may include a datatransmission queue for each of a plurality of frequency bands includingat least a first data transmission queue for a first frequency band anda second data transmission queue for a second frequency band; amulti-band scheduler configured to receive data units, and to assigneach data unit to one of the data transmission queues for one of thefrequency bands; a resource scheduler for each of the plurality offrequency bands, including at least: a first resource schedulerconfigured to schedule data units from the first data transmission queuefor transmission via resources of the first frequency band; and a secondresource scheduler configured to schedule data units from the seconddata transmission queue for transmission via resources of the secondfrequency band.

For example, a method may include using a first frequency band forcommunication, the first frequency band being dedicated to a networkoperator; making a determination that a second frequency band isavailable for use, the second frequency band, at least in some areas,being shared among a plurality of network operators or between a networkoperator and other radio technologies; and using the second frequencyband based on the determination, in addition to the first frequencyband.

The details of one or more implementations are set forth in theaccompanying drawings and the description below.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram illustrating a wireless network according toan example embodiment.

FIG. 2 is a block diagram illustrating a wireless network according toan example embodiment.

FIG. 3 is a block diagram illustrating a wireless network according toan example embodiment.

FIG. 4 is a diagram illustrating multiple frequency bands that may beused by a base station according to an example embodiment.

FIG. 5 is a diagram illustrating a multi-band wireless network accordingto an example embodiment.

FIG. 6 is a diagram illustrating operation of a multi-band wirelessnetwork in a downlink direction according to another example embodiment.

FIG. 7 is a diagram illustrating a wireless network that includes amulti-band relay node according to an example embodiment.

FIG. 8 is a diagram of a wireless network according to another exampleembodiment in which an ARQ or automatic repeat request type process isused.

FIG. 9 is a block diagram of a wireless node according to an exampleembodiment.

FIG. 10 is a flow chart illustrating operation of a wireless nodeaccording to an example embodiment.

FIG. 11 is a flow chart illustrating operation of a wireless nodeaccording to another example embodiment.

FIG. 12 is a flow chart illustrating operation of a wireless nodeaccording to another example embodiment.

FIG. 13 is a flow chart illustrating operation of a wireless nodeaccording to another example embodiment.

FIG. 14 is a flow chart illustrating operation of a wireless nodeaccording to another example embodiment.

FIG. 15 is a flow chart illustrating operation of a wireless nodeaccording to yet another example embodiment.

FIG. 16 is a block diagram illustrating an apparatus that may beprovided in a wireless node according to an example embodiment.

DETAILED DESCRIPTION

Referring to the Figures in which like numerals indicate like elements,FIG. 1 is a block diagram illustrating a wireless network according toan example embodiment. Wireless network 102 may include a number ofwireless nodes or stations, such as a wireless infrastructure node 104(which may include an access point (AP) or base station, relay station,a node B, or the like), and one or more mobile nodes or mobile stations(or user equipment or user terminals), such as wireless nodes 106 and108. While only one infrastructure node 104 and two wireless nodes ormobile stations (or user equipment or user terminals) 106, 108 are shownin wireless network 102, any number may be provided. Each wireless node,e.g., nodes 106, 108, in network 102 may be in wireless communicationwith the wireless infrastructure node 104, and may even be in directcommunication with each other. Wireless infrastructure node 104 may becoupled to a fixed network, such as a Local Area Network (LAN), WideArea Network (WAN), Radio Access Network (RAN), the Internet, etc., andmay also be coupled to other wireless networks or to otherinfrastructure nodes.

FIG. 2 is a block diagram illustrating a wireless network according toan example embodiment. According to an example embodiment, a mobilestation MS 208 may initially communicate directly with a base station BS204, for example, and a subscriber station 210 may communicate with thebase station BS 204 via a relay station RS 220. In an exampleembodiment, the mobile station 208 may travel or move with respect tobase station BS 204. For example, the mobile station MS 208 may move outof range of the base station BS 204, and may thus begin communicatingwith the base station 204 via the relay station 220 as shown in FIG. 2.Therefore, the use of relay nodes or relay stations may extend the rangeand improve the coverage of the cell or network. Thus, a wirelessnetwork that employs one or more relay nodes or relay stations may be anexample of a multi-hop wireless network and may sometimes be referred toas a relay enhanced cell, a relay network, or the like.

FIG. 3 is a block diagram illustrating a wireless network 302 accordingto an example embodiment. Wireless network 302 may include a number ofwireless nodes or stations, such as base station BS1 304, relay stationsRS1 320 and RS2 330, a group of mobile stations, such as MS1 322 and MS2324 communicating with relay station RS1 320, and MS3 332 and MS4 334communicating with relay station RS2 330. As shown, relay station RS2330 also communicates with relay station RS1 320. While only one basestation, two relay stations, and four mobile stations are shown inwireless network 302, any number of base stations, relay stations (alsoreferred to as relay nodes), and mobile stations or mobile nodes (alsoreferred to as user terminals) may be provided. The base station 304 maybe coupled to a fixed network 306, such as a Wide Area Network (WAN),the Internet, etc., and may also be coupled to other wireless networks.The group of stations MS1 322, MS2 324, and RS2 330 may communicate withthe base station BS1 304 via the relay station RS1 320. The group ofstations MS3 332, MS4 334, may communicate with the base station BS1 304via the relay station RS2 330, which communicates with the base stationBS1 304 via the relay station RS1 320.

The various embodiments described herein may be applicable to a widevariety of wireless network technologies, such as, for example, WLAN(wireless local area network) networks (e.g., IEEE 802.11 typenetworks), IEEE 802.16 Wi MAX networks, cellular networks, relaynetworks, multi-hop networks, 3GPP related networks including Long TermEvolution (LTE) of 3GPP, HSDPA (high speed downlink packet access), UMTSTerrestrial Radio Access Network (UTRAN), wireless networks based onorthogonal frequency division multiplexing (OFDM), orthogonal frequencydivision multiple access (OFDMA) or other techniques, radio networks, orother wireless networks. These are merely some example networks ortechnologies, and the various embodiments described herein are notlimited thereto. In another example embodiment, the various examples andembodiments may be applied, for example, to a mesh wireless network,where a plurality of mesh points (e.g., Access Points) may be coupledtogether via wired or wireless links. The various embodiments describedherein may be applied to wireless networks, both in an infrastructuremode, as well as an ad-hoc mode in which wireless nodes or stations maycommunicate directly via a peer-to-peer network, for example.

The term “wireless node” or “node,” or wireless station or the like, mayinclude, for example, a wireless mobile device, mobile station or userequipment, an access point (AP), base station or other infrastructurenode, a wireless personal digital assistant (PDA), a cell phone, an802.11 WLAN phone, a wireless mesh point, or any other wireless device.An infrastructure node may include, as examples, a base station, anaccess point, a relay station or relay node, a node-B, or any otherinfrastructure node. These are merely a few examples of the wirelessdevices that may be used to implement the various embodiments describedherein, and this disclosure is not limited thereto.

According to an example embodiment, one or more wireless nodes (e.g.,base stations, relay nodes, and/or mobile nodes/user terminals) in awireless network or relay enhanced cell may include wireless (or radio)interfaces for each of a plurality of frequency bands. One or more ofthe wireless nodes in a wireless network may have the capability oftransmitting and receiving on multiple frequency bands, for example.

FIG. 4 is a diagram illustrating multiple frequency bands that may beused by a base station (or access point or Node B) according to anexample embodiment. A base station may be able to transmit and receivesignals via multiple frequency bands, such as a basic or “B” band 410and an extended or “E” band 412. Or these frequency bands may bereferred to as a first frequency band (or first band) and a secondfrequency band (or second band), or vice versa, for example. Althoughonly two frequency bands are illustrated, the base station (and othernodes in a wireless network) may be capable of transmitting and/orreceiving signals on any number (e.g., 2, 3, 4, 5, 6,) of frequencybands. For example, the basic or B band may be provided at a band around900 MHz, while the extended or E band may be provided at around 3.5 GHz.These are merely examples, and any frequencies may be used for thefrequency bands that are used by the wireless nodes.

FIG. 5 is a diagram illustrating a multi-band wireless network accordingto an example embodiment. According to an example embodiment, thewireless network of FIG. 5 may be a relay enhanced cell, having a basestation (BS) 510, one or more relay nodes (RN), and one or more userterminals (UT). BS 510 may include wireless interfaces for both B bandand E band. For example, due to a lower frequency range (e.g., 900 MHz)of B band (and therefore, e.g., lower attenuation) as compared to E band(e.g., 3.5 GHz), BS 510 may be able to provide direct service to anumber of UTs within a significant coverage area, such as to UTs 514,518. Relay nodes (RNs) 522, 524 and 526 may transmit and receive in Eband this example. For example, RN 522 may forward signals received viaE band from BS 510 to RN 524 via E band. RN 524 may then forward thesesignals via E band to UT 516. RN 526 may similarly forward signalsbetween BS 510 and UT 520 via E band. Signal paths for B band are shownby dashed lines, while signal paths for E band are shown with solidlines. For example, there may be a group of UTs that cannot be reachedvia B band (e.g., UTs with an E band only interface, or UTs that areoutside the direct range of BS 510 via B band). Thus, in this example,BS 510, as a multi-band device, may communicate via both B and E bands,for example, or via any number of frequency bands.

FIG. 6 is a diagram illustrating operation of a multi-band wirelessnetwork in a downlink direction according to another example embodiment.In the example of FIG. 6, BS 610 may transmit data on B band, E band orboth bands, while RNs may communicate via E band (in this example), andUTs (UT1 and UT2) may communicate via both B band and E band. Packetsdirected to one or both UTs arrive at the BS 610, and may be segmentedinto one or more smaller data units, such as cells, radio transmissionunits, etc., for transmission, or may be transmitted as packets. BS 610may then transmit the data units to UT1 and UT2 via B band, E band, or acombination of B and E bands, for example.

For example, referring to FIG. 6, in order to provide load balancing orsubstantially balance the traffic loads on B and E bands, BS 610 maytransmit data units to UT1 and UT2 via both E band and B band. Forexample, BS 610 may include a multi-band scheduler (MBS) to scheduledata units for transmission via multiple bands. For example, BS 610 mayinclude a MBS to schedule a data unit for transmission on B band or Eband, for example, which may be transmitted to UT1 or UT2. The dataunits (e.g., packets or radio transmission units, cells . . . )scheduled by the MBS of BS 610 for transmission to UT1 and UT2 are shownin FIG. 6, with data units being transmitted via B band and E band forboth UT1 and UT2. This may allow, for example, BS 610 to approximatelybalance the traffic load on two or more available frequency bands thatare serving a UT or mobile node, e.g., UT1 and UT2. For example, the MBSof BS 610 may transmit one or more data units to UT2 via B band, and maytransmit one or more packets to UT2 via E band and via RN 612. BS 610may similarly transmit a flow or stream of packets to UT1 via both Bband and E band.

FIG. 7 is a diagram illustrating a wireless network that includes amulti-band relay node according to an example embodiment. BS 710 mayinclude a MBS and may transmit on one or both bands, B band and/or Eband, as an example. RN 712 may also include a MBS and may transmit onboth B band and E band. In this example, BS 710 transmitted two dataunits to RN 712 via E band. RN 712 may receive these two data units viaE band, and, based on a decision or determination of the MBS of RN 712,RN 712 may transmit one of the data units via B band to UT1, and theother data unit via E band to UT1. The data unit transmitted from RN 712via E band may be relayed by RN 714 to UT1. Thus, the MBS of RN 712 mayschedule received data units for transmission on a same band or adifferent band on which they were received. Thus, with a MBS, data unitsreceived via E band may be scheduled for transmission to UT1 via eitherE band or B band, or both. In this example, the first and second dataunits received via E band are forwarded to UT1 via B band and E band,respectively, as shown. Thus, for example, an MBS of an infrastructurenode may received data units via a first band, and schedule the dataunits for transmission via a second band, or a combination of frequencybands, depending on the situation, for example.

For example, link quality or delay may be more favorable for the B band(e.g., since fewer hops), as compared to the E band. Thus, a stream orflow of data units that have requested low delay or relatively high QoS(quality of service) may be received by an MBS of a RN via E band, andthen scheduled for transmission over a band (or bands) that provides therequested delay or QoS requirements for the flow or data units, e.g.,via band B.

FIG. 8 is a diagram of a wireless network according to another exampleembodiment in which an ARQ or automatic repeat request type process isused. A number of different kinds of ARQ processes may be used, and afew examples are mentioned here, but the disclosure is not limitedthereto. According to an example embodiment, one or more ARQ (automaticrepeat request) processes may be used to provide error control or dataunit retransmission. ARQ may include, for example, the use of areceiving node sending an acknowledgement (ACK) or block acknowledgementto indicate when a data unit was successfully received, or a negativeacknowledgement (NAK) to indicate when a corrupted data unit wasreceived. A sending node may, for example, retransmit the data unit ifthe sending node received a NAK, or a timeout occurred before thesending node received an ACK or other indication that the data unit wassuccessfully received.

As another example, a hybrid ARQ (HARQ) process in which data units areencoded using an error-correction code (e.g., Reed Solomon code or Turbocode) and error-detection information (e.g., CRC or cyclic redundancycheck) is appended to the data unit before transmission orretransmission. Or, for example, a chase combining HARQ process may beused in which the transmitted data unit may be coded and retransmitted.Or, an incremental redundancy HARQ process may be used in which a dataunit may be retransmitted using a different coding rate and/or differentpuncturing techniques, as compared to transmission of the original dataunit. Other ARQ processes may be used.

Referring to FIG. 8, an end-to-end (E2E) ARQ process may be providedbetween the base station (BS) and a user terminal (UTA). RN1, in thisexample embodiment, may include an MBS, which may allow RN1 to transmit(or retransmit) data units on a selected frequency band of a pluralityof frequency bands, and which may be a different band than the data unitwas received with. A hybrid ARQ process may be provided between RN2 andUTA, for example.

The E2E ARQ between BS and UTA may provide reliable data transmissionbetween BS and UT, e.g., in the case of handovers in a single band (“E”band for example in which original transmissions from the BS to UTA areprovided via E band). Although not shown, a data unit may be initiallyforwarded from BS to UTA via E band. However, in this example the dataunit is not successfully received at UTA. The BS-UTA E2E ARQ maytypically cause BS to retransmit the data unit. However, in thisexample, as shown in FIG. 8, there may also be an E2E ARQ providedbetween RN1 and UTA. If the Hop ARQ transmission on E band (between RN2and UTA) was not successful, then RN1 may retransmit the data unit via Eband or B band. A retransmission from RN1 via B band directly to UTA isshown in FIG. 8.

For example, RN1 may monitor measurement results (e.g., channel qualityindications or CQI for a channel on B band and another channel on Eband) that the UTA (user terminal A) may send to RN1 for handoverpurposes, e.g., received signal strength of radio access points (e.g.,RSSI signals relating to RN1 via band B and RN2 via band E). Forexample, the UT may be served by RN2 via E band or via B band directlyfrom RN1. If RN1 B band starts to become a candidate to transmit to UTA,then RN1 may request a block ACK (or a periodic block ACK) from the RN2that is currently serving UTA. RN1 may also request an acknowledgementor block ACK from UTA. The period for RN2 reporting block ACKs to RN1may be shorter than the time interval for E2E ARQ between BS and UT, forexample. Based on the received block ACKs and channel qualityindications, RN1 may decide to move UTA to B band and initiateretransmission via B band. The decision to move or transfer the UTA to Bband may also be based on a variety of other factors, such as delayrequirements or QoS criteria of a flow or application providing the dataunits.

To move the UTA from band E to band B, RN1 may perform a contexttransfer. A transmission data queue may be provided within RN1 for eachband (band E and band B). Also, control data may be stored in RN1relating to any data transfers and retransmissions, such as data unitsthat are not yet successfully received, or which data units have beenretransmitted, etc. For example, a context transfer may includetransferring data units stored in a first data transmission queueassociated with the E band to a second data transmission queueassociated with the B band, at RN1, for example. Also, as part of thecontext transfer, control data associated with the transmission of datavia the original band or associated with a flow or group of data unitsmay be reassigned (or transferred) from the old band (band E in thisexample) to the new band (band B in this example). The transfer of dataunits may involve physically moving data units from the first datatransmission queue to the second data transmission queue, or may involveproviding an indication in memory or in the queues that the data unitshave been reassigned to the second (or new) frequency band. Similarly,the reassignment of control data may involve physically moving such datafrom a buffer or memory area associated with the old (or first) band toa buffer or memory area associated with the new or second band, or mayinvolve providing an indication that such control data is now assignedto the second or new band (band B in this example). More details areprovided below regarding an example MBS (multi-band scheduler) and theuse of data transmission queues at a multi-band wireless node.

Referring to FIG. 8, in one example embodiment, the UTA may move (e.g.,via context transfer) to the B band to receive the retransmissions fromRN1, and then may return (e.g., via context transfer) to the E band tobe served by RN2 again. In such case, the UTA may signal RN2 that itwill not be available. After receiving the retransmissions from RN1 viaB band, UTA may (e.g., perform a context transfer to E band) return tothe E band and send, via E band, a block ACK to RN2, or may send an ARQor HARQ status report to RN2 to indicate which data units have beenreceived, for example. Thus, RN2 may receive an indication of whichpackets the UTA has received correctly and it can remove those dataunits from its buffer or transmission queues (e.g., and may initiateretransmission of other data units per the ARQ or HARQ process that hasbeen implemented).

FIG. 9 is a block diagram of a wireless node according to an exampleembodiment. The wireless node 900 may be a base station or access point,a relay node, or a user terminal or mobile station. Although thestructure or implementation may be different for different kinds ofwireless nodes.

Referring to FIG. 9, for example, as a base station or AP, networkpackets may be received and segmented into smaller units fortransmission by segmentation and reassembly block 910. These smallerunits may be referred to as data units or radio transmission units, orother units. The data units are stored in RLC (radio link control)buffers 912. A RLC buffer 912 may be provided for each frequency band,e.g., RLC buffer 912B to store data units received via band B, and RLCbuffer 912E to store data units received via band E, as an example.

An end-to-end (E2E) ARQ process may be provided, e.g., between the nodeand a user terminal, such as UTA (user terminal A). The ARQ process 914(which may be considered an outer ARQ) may include adding a MAC (mediaaccess control) address, a transmission sequence number, and a CRCchecksum for error detection. The RLC layer may be provided in the basestation and/or relay nodes.

A multi-band scheduler (MBS) 916 may schedule the data units (or radiotransmission units) for transmission in one of a plurality of frequencybands. In this example, two bands are shown, B band and E band, but anynumber of bands may be provided. MBS 916 may, for example, store dataunits in a selected data transmission queue to await transmission overthe selected frequency band. For example, if band B was selected by MBS916 for transmission, the data unit may be placed in data transmissionqueue 918B for B band. If band E was selected by MBS 916 fortransmission, the data unit may be placed in data transmission queue918E for E band.

A separate inner ARQ process, such as a HARQ (Hybrid ARQ) process 920may be provided for some flows for each frequency band. This inner ARQmay be, for example, a HARQ process 920B for B band, and a HARQ process920E for E band. HARQ may be, for example, a 1-hop ARQ process and maybe a variation of the ARQ error control method. As part of each HARQprocess, the data unit may be encoded (e.g., using Turbo code orReed-Solomon code, or other code) and a CRC may be added for errordetection, and a sequence number may be added for retransmissions. Ablock of data may be encoded, and therefore, the transmitted data unitsfrom each HARQ may in some cases be referred to, for example, as FEC(forward error correction) blocks or other data units. Or these unitsmay simply be referred to as data units, which may include FEC blocks orother data units.

The HARQ processes 920 in FIG. 9 may be any type of HARQ process, suchas chase combining HARQ, or incremental redundancy HARQ, or other HARQprocess. In chase combining, a data unit that was originally transmittedis retransmitted, and the destination node may use both copies (originaland retransmission copies) of the data unit to improve decoding. Thismay involve resending the same encoded bits. In incremental redundancy,a different set of encoded bits may be sent in the retransmission, e.g.,by using a different coding rate and/or different puncturing pattern forthe retransmitted data unit (as compared to the originally transmitteddata unit). Data may be coded, punctured and interleaved beforetransmission, according to an example embodiment.

The MBS 916 may enable fast switching between multiple frequency bandsor simultaneous operation on multiple bands. MBS 916 may distribute thedata units to the available bands (e.g., band B and band E). A queuemonitor or queue monitoring block 919 may monitor the status of the datatransmission queues 918B and 918E, and may monitor the delays or averagedelay in each data transmission queue. The queue monitoring block 919may facilitate or assist in the prioritization of retransmissions,reschedule packets if delays in a queue for a band increase beyond athreshold, and further may facilitate or assist with band changesbetween user terminals or for flows or other groups of data units.

A context transfer may be performed to allow for or facilitate a bandchange (a use of a new frequency band for data transmission). Thecontext transfer may be performed for all data units, for a flow of dataunits, for data units addressed to or directed to a user terminal, orfor data units of a specific QoS or traffic type, as examples.

A context transfer may include, for example, transferring data unitsstored in a first data transmission queue associated with a firstfrequency band to a second data transmission queue associated with asecond frequency band (e.g., transferring data units from queue 918B toqueue 918A or vice versa). This may involve physically transferring dataunits between different queues or buffers or may involve merelyreassigning the data units to the new data queue or frequency band, suchas, e.g., providing an indication or field in memory indicating theassociation of the data unit(s) to the new band or queue. The dataqueues may be physically separate queues or may be part of shared memoryused by both frequency bands for transmission. For example, eachresource scheduler 922 may have access to transmission queues ofmultiple or all frequency bands. Thus, for example, data units may bestored in memory or a buffer, and an indication may be provided in thememory or buffers for each data unit identifying the associatedfrequency band or frequency band for which the data unit has beenassigned by the MBS, and this band assignment data may be updated for atleast some data units during a context transfer, for example. Thecontext transfer may also include assigning newly received data units ofthe transferred flow to the new (or second) frequency band or assigningthe new data units to the data transmission queue associated with thenew band.

The context transfer may also include reassigning control dataassociated with a frequency band to a new frequency band. This controldata may relate to the transmission and/or retransmission of data overthe band, such as, for example: which data units have been transmitted,which data units have been retransmitted, incremental redundancyinformation for retransmitted data (e.g. redundancy versions of the datathat have already been retransmitted), a requested QoS or delayconstraints of a flow or other information describing the flow, and/orother information.

The context transfer may be performed, for example, for all data unitsflowing through a node (or received by or transmitted from a node), ormay be performed for a flow (a per flow context transfer), perapplication or per user terminal context transfer (e.g., transfer dataunits and/or control data originated by a specific application ordirected to a specific user terminal). Both before and after a contexttransfer, a same flow ID, and a same user terminal ID, and samedestination address, may be used.

A single flow of data units may be transmitted on a single band, or asingle flow may be transmitted across two or more bands. Thus, one(common) set of data unit sequence numbers may be used for data unitstransmitted as part of a flow or to a user terminal, for example, evenwhen multiple bands are used to transmit the flow. This may allow adestination or receiving node to recombine the data units of the flow ina proper order that were transmitted over different bands, based ondecisions of the MBS 916. In another example embodiment, a common (orone) set of sequence numbers used for a flow or user terminal for afirst frequency band may be continued for transmissions via a newfrequency band after a context transfer for the flow or user terminal tothe new band.

Referring to FIG. 9, a resource scheduler 924 may be provided for eachfrequency band to schedule data units for transmission via resources ofthe frequency band. For example, a resource scheduler 922B for B bandmay map bits from data transmission queue 920B onto wireless mediaresources (e.g., channels and/or subchannels) of B band for transmission(e.g., map bits onto channels or subchannels/subcarriers of B Band).Each channel may include, for example, one or more subcarriers or timeslots. Similarly, resource scheduler 922E for E band may map bits fromdata transmission queue 920E onto wireless media resources (e.g.,channels and/or subchannels) of the E band (e.g., map bits ontosubcarriers of E Band).

In an example embodiment, each resource scheduler 922B, 922E, etc., mayhave access to at least the data stored in the associated datatransmission queue, and may obtain channel state information or channelquality indications or CQI (e.g., RSSI or SINR information) for thechannels of the associated frequency band to allow the resourcescheduler to select a best group of channels or a subset of channels tobe used for transmission within the frequency band. As described below,according to an example embodiment, a data unit may be transmitted via afirst frequency band, and then (e.g., after a context transfer)retransmitted on a second frequency band, as part of an ARQ or HARQprocess.

In an example embodiment, synchronization between the two bands may beprovided as part of a context transfer, or prior to context transfer. Itmay be desirable, at least in some situations, to reduce the period oftime the user terminal needs to stay synchronized with both bands. Tofacilitate synchronization or a fast context transfer, a message may besent from the infrastructure node to the user terminal indicating a timeshift between the two bands (e.g., the time shift of the beginning ofthe next frame on the other band or new band), frequency shift betweenthe two bands or between the two channels used of the two bands, and/orother system information such as position of the allocation table orresource allocation table. In some cases, the band switch (e.g., thelocation or identity of the new frequency band) may be known in advanceand preparations may be started. For example, if the BS knows that the Eband is not available anymore after 5 ms, then it can request the userterminal or mobile node to synchronize with the B band. The UT may alsoestimate the path loss or channel state or provide a channel qualityindication to the infrastructure node or BS before switching to the Bband (new band in this example). When the UT switches the band thischannel or CQI information may be forwarded from the E band resourcescheduler to the B band resource scheduler, for example.

FIG. 10 is a flow chart illustrating operation of a wireless nodeaccording to an example embodiment. The method may include transmitting,from a wireless node, a first data unit via a first channel of a firstfrequency band of a plurality of frequency bands 1010, selecting asecond frequency band of the plurality of frequency bands 1020,performing a context transfer at the wireless node from the firstfrequency band to the second frequency band 1030, and transmitting, fromthe wireless node, a second data unit via a second channel of the secondfrequency band 1040.

For example, the first channel may include one or more subcarrierswithin the first frequency band, and the second channel may include oneor more subcarriers within the second frequency band.

In an example embodiment, the performing a context transfer (1030) mayinclude reassigning data units and associated control data from thefirst frequency band to the second frequency band.

In an example embodiment, the performing a context transfer (1030) mayinclude transferring data units stored in a first data transmissionqueue associated with the first frequency band to a second datatransmission queue associated with the second frequency band, andre-assigning control data associated with the first frequency band fromthe first frequency band to the second frequency band.

In an example embodiment, the performing a context transfer (1030) mayinclude transferring or re-assigning data units and associated controldata that are assigned to a first resource scheduler associated with thefirst frequency band to a second resource scheduler associated with thesecond frequency band.

In an example embodiment, the flow chart illustrated in FIG. 10 mayfurther include retransmitting, after performing the context transfer,the first data unit via the second channel of the second frequency band.In an example embodiment, the retransmitting the first data unit via thesecond channel of the second frequency band may be part of: an automaticrepeat request (ARQ) process; a hybrid ARQ (HARQ) process in which dataunits are encoded using an error-correction code (e.g., Reed Solomoncode or Turbo code) and error-detection information (e.g., CRC or cyclicredundancy check) is appended to the data unit before transmission orretransmission; a chase combining HARQ process in which the first dataunit is coded and retransmitted via the second channel of the secondfrequency band; and/or an incremental redundancy HARQ process in whichthe first data unit transmitted via the first channel of the firstfrequency band and the retransmitted first data unit retransmitted viathe second channel of the second frequency band are encoded differentlyor coded using different coding rates and/or different puncturingtechniques.

In an example embodiment, an apparatus may include a wirelesstransceiver, a controller or processor, memory, and a multi-bandscheduler (such as MBS 916, FIG. 9). The apparatus may be configured totransmit, from a wireless node, a first data unit via a first channel ofa first frequency band of a plurality of frequency bands; select asecond frequency band of the plurality of frequency bands; perform acontext transfer at the wireless node from the first frequency band tothe second frequency band; and transmit, from the wireless node, asecond data unit via a second channel of the second frequency band.

The apparatus may be, for example, one of: a wireless access point, basestation, or node B; a wireless relay node or relay station; or awireless user terminal or mobile station.

FIG. 11 is a flow chart illustrating operation of a wireless nodeaccording to another example embodiment. The flow chart of FIG. 11 mayinclude transmitting one or more data units of a group of data units viaa first channel of a first frequency band in a wireless network using anARQ process (1110); re-assigning the group of data units and associatedcontrol data from the first frequency band to a second frequency band(1120); and continuing to transmit the group of data units via a secondchannel of the second frequency band using the ARQ process (1130).

In an example embodiment, the group of data units may include one of: aflow of data units; data units directed to or addressed to a specificwireless user terminal, mobile station or destination address; or dataunits designating one or more specific QoS (quality of service)requirements.

In an example embodiment, an apparatus may include a wirelesstransceiver (1602), and a multi-band scheduler (e.g., MBS 916). Theapparatus may be configured to: transmit one or more data units of agroup of data units via a first channel of a first frequency band in awireless network using an ARQ process; re-assign the group of data unitsand associated control data from the first frequency band to a secondfrequency band; and continue to transmit the group of data units via asecond channel of the second frequency band using the ARQ process.

FIG. 12 is a flow chart illustrating operation of a wireless nodeaccording to another example embodiment. In an example embodiment, theflow chart of FIG. 12 may include transmitting a data unit via a firstchannel of a first frequency band in a wireless network using an ARQprocess (1210); failing to receive an indication that the data unit wassuccessfully received (1220); performing a context transfer from thefirst frequency band to a second frequency band, including re-assigningone or more data units, including the transmitted data unit, and atleast some associated control data of the one or more data units, fromthe first frequency band to the second frequency band (1230); andretransmitting the transmitted data unit using a second channel of thesecond frequency band according to the ARQ process (1240).

In another example embodiment, an apparatus may be provided for use in awireless node including: a wireless transceiver, and a controller. Theapparatus (or the controller) may be configured to: transmit a data unitvia a first channel of a first frequency band in a wireless networkusing an ARQ process; fail to receive an indication that the data unitwas successfully received; perform a context transfer from the firstfrequency band to a second frequency band, including re-assigning one ormore data units, including the transmitted data unit, and at least someassociated control data of the one or more data units, from the firstfrequency band to the second frequency band; and retransmit thetransmitted data unit using a second channel of the second frequencyband according to the ARQ process.

FIG. 13 is a flow chart illustrating operation of a wireless nodeaccording to another example embodiment. The flow chart of FIG. 13 mayinclude transmitting data via a first channel on a first frequency bandof a plurality of frequency bands in a wireless network (1310);detecting a condition relating to the first frequency band (1320);reassigning (or transferring) at least some control data relating to thefirst frequency band to a second frequency band of the plurality offrequency bands (1330); transferring data stored in data transmissionqueues associated with the first frequency band to data transmissionqueues associated with the second frequency band (1340); andtransmitting the transferred data via the second frequency band (1350).

According to another example embodiment, an apparatus may include awireless transceiver, and a controller. The apparatus (or thecontroller) may be configured to: transmit data via a first channel on afirst frequency band of a plurality of frequency bands in a wirelessnetwork; detect a condition relating to the first frequency band;reassign at least some control data relating to the first frequency bandto a second frequency band of the plurality of frequency bands; transferdata stored in data transmission queues associated with the firstfrequency band to data transmission queues associated with the secondfrequency band; and transmit the transferred data via the secondfrequency band.

FIG. 14 is a flow chart illustrating operation of a wireless nodeaccording to another example embodiment. The flow chart of FIG. 14 mayinclude receiving one or more data units of a flow at a wireless node(1410); assigning each received data unit of the flow to a firstfrequency band of a plurality of frequency bands (1420); determining aband transfer condition for the flow (1430); and performing a contexttransfer from the first frequency band to a second frequency band forthe flow based on the determined band transfer condition (1440).

In an example embodiment, the receiving one or more data units of a flowat a wireless node (1410) may include: receiving one or more packets;and segmenting each packet into one or more radio transmission units orother data units for transmission.

In an example embodiment, the assigning each received data unit of theflow (1420) may include assigning each received data unit of the flow toa first frequency band of a plurality of frequency bands. In an exampleembodiment, the assigning (1420) may be performed based on one or moreof the following: a channel quality indication or other measurement forone or more of the frequency bands; quality of service constraints orrequirements of the flow as compared to a quality of service beingprovided by each of the plurality of frequency bands; and an amount oftraffic, load or congestion on one or more of the frequency bands.

In an example embodiment, the determining a band transfer condition(1430) may include determining or detecting one or more of: anunavailability of at least a portion (e.g., channel or subchannel) ofthe first frequency band for the flow; a network congestion or trafficload on at least a portion (e.g., channel or subchannel) of the firstfrequency band that exceeds a congestion threshold; a channel qualityindication for at least a portion (e.g., channel or subchannel) of thefirst frequency band that identifies a channel quality less than achannel quality threshold; a Quality of Service (QoS) for at least aportion (e.g., channel or subchannel) of the first frequency band isless than a QoS required or requested by the flow; a network congestionor traffic level of at least a portion (e.g., channel or subchannel) ofthe first frequency band is higher than a network congestion or trafficlevel for at least a portion of the second frequency band; a channelquality of at least a portion (e.g., channel or subchannel) of thesecond frequency band is a higher or more favorable quality than atleast a portion of the first frequency band; and/or a QoS of at least aportion (e.g., channel or subchannel) of the second frequency band ishigher than the QoS of at least a portion of the first frequency band.

In an example embodiment, the performing a context transfer from thefirst frequency band to a second frequency band for the flow based onthe determined band transfer condition (1440) may include transferringdata units stored in a first data transmission queue associated with thefirst frequency band to a second data transmission queue associated withthe second frequency band; re-assigning control data associated with thefirst frequency band from the first frequency band to the secondfrequency band; and assigning any newly received data units for the flowto the second frequency band.

FIG. 15 is a flow chart illustrating operation of a wireless nodeaccording to yet another example embodiment. The flow chart or method ofFIG. 15 may include receiving one or more data units of a first flow ata wireless node (1510); assigning each received data unit of the firstflow to a first frequency band of a plurality of frequency bands (1520);receiving one or more data units of a second flow at a wireless node(1530); assigning each received data unit of the second flow to a secondfrequency band of the plurality of frequency bands (1540); determining aband transfer condition for the first flow (1550); and performing acontext transfer from the first frequency band to the second frequencyband for the first flow based on the determined band transfer condition(1560).

In an example embodiment, the performing a context transfer (1560) mayinclude assigning one or more of the data units of the first flow, andassociated control data, to the second frequency band.

In an example embodiment, the flow chart of FIG. 15 may further includetransmitting, before performing the context transfer, data units of thefirst flow via a first channel of the first frequency band;transmitting, after performing the context transfer, data units of thefirst flow via a second channel of the second frequency band; andtransmitting data units of the second flow via a third channel of thesecond frequency band.

In another example embodiment, a multi-band scheduler (such as MBS 916,FIG. 6) may be provided for use in a wireless node. The multi-bandscheduler may be configured to: receive one or more data units of aflow; assign each received data unit of the flow to a first frequencyband of a plurality of frequency bands; determine a band transfercondition for the flow; and perform a context transfer from the firstfrequency band to a second frequency band for the flow based on thedetermined band transfer condition.

In yet another example embodiment, an apparatus may include a datatransmission queue for each of a plurality of frequency bands includingat least a first data transmission queue for a first frequency band anda second data transmission queue for a second frequency band; amulti-band scheduler (e.g., MBS 916) configured to receive data units,and to assign each data unit to one of the data transmission queues forone of the frequency bands; a resource scheduler for each of theplurality of frequency bands, including at least: a first resourcescheduler configured to schedule data units from the first datatransmission queue for transmission via resources of the first frequencyband; and a second resource scheduler configured to schedule data unitsfrom the second data transmission queue for transmission via resourcesof the second frequency band.

The apparatus may be configured to perform a context transfer from thefirst frequency band to the second frequency band, includingtransferring data units from the first data transmission queue to thesecond data transmission queue; and reassigning control data associatedwith the transferred data units, from the first frequency band or thefirst resource scheduler to the second frequency band or the secondresource scheduler.

According to another example embodiment, B band may be dedicated to anetwork operator, while E band may be shared among multiple networkoperators (depending on the area). For example, where use of the E bandis not prohibited, a network may communicate via the E band, e.g., toextend coverage or provide additional services or higher throughput, orlower network latency service, etc., through the additional capacity ofthe E band. For example, a satellite operator may prohibit transmissionsor usage of the E band within a specific range (e.g., 50 km) of thesatellite base stations. Thus, when a 4G (or other network operator) APor BS is outside this exclusion range, then the 4G network may also usethe extension band (E band), in addition to the B band which may bededicated to the 4G network operator.

As an example, the extension (E) band may be shared among multiplenetwork operators of the same technology, such as among two WiMAXnetwork operators. Or, the E band may be shared (when not prohibited)among network operators of different technologies, such as between asatellite operator (or satellite network operator) and a 4G networkoperator, for example. Thus, the network operator may always use theirdedicated frequency band (e.g., B band), and when not prohibited (e.g.,not within the exclusion zone for E band), the network operator may alsouse the extension (or E band).

For example, when a network is using two frequency bands, (e.g., B bandand E band), then control data or other important signals may becommunicated via the dedicated band (e.g., B band), while data or lowerpriority signals may be communicated via the Extension band or E band.

In another example embodiment, a frequency band may be shared amongtechnologies where there may not be a network operator, such as forradar (as an example). Thus, a radar user may share the frequency bandwith a network operator or user of another technology, such as cellular,WiMAX, etc. The term network operator may therefore encompass users ofthe frequency band in such situations.

For example, a method may include using a first frequency band forcommunication, the first frequency band being dedicated to a networkoperator; making a determination that a second frequency band isavailable for use (e.g., determining that an infrastructure node isoutside of an exclusion zone or is not otherwise prohibited from usingthe second frequency band), the second frequency band, at least in someareas, being shared among a plurality of network operators; and usingthe second frequency band based on the determination, in addition to thefirst frequency band.

In an example embodiment, the second frequency band may be shared amongnetwork operators of a same technology (e.g., two WiMAX operators). Or,in another example embodiment, the second frequency band may be sharedamong network operators of a different technology (e.g., 4G andsatellite operators sharing the extension band).

According to another example embodiment, a method may include using afirst frequency band to transmit data units of a first priority type;and using a second frequency band to transmit data units of a secondpriority type. For example, high priority traffic, e.g., VoIP (Voiceover IP) packets or data units may be communicated via a first frequencyband (B band). And, lower priority traffic (e.g., data or best effortstraffic) may be communicated via a second frequency band (e.g., E band).User terminals may in some cases be charged extra (or may pay anadditional amount) to receive wireless services over the high priorityor extension band, for example.

FIG. 16 is a block diagram illustrating an apparatus 1600 that may beprovided in a wireless node according to an example embodiment. Thewireless node may include, for example, a wireless transceiver 1602which may include a transmitter to transmit signals and a receiver toreceive signals, a controller 1604 to control operation of the stationand execute instructions or software, and a memory 1606 to store dataand/or instructions. The apparatus 1600 may further include a MBS 916,such as described above with respect to FIG. 9.

Controller (or processor) 1604 may be programmable and capable ofexecuting software or other instructions stored in memory or on othercomputer media to perform the various tasks and functions describedherein.

In addition, a storage medium 1606 may be provided that includes storedinstructions, when executed by a controller or processor that may resultin the controller 604, or other controller or processor, performing oneor more of the functions or tasks described herein.

Implementations of the various techniques described herein may beimplemented in digital electronic circuitry, or in computer hardware,firmware, software, or in combinations of them. Implementations mayimplemented as a computer program product, i.e., a computer programtangibly embodied in an information carrier, e.g., in a machine-readablestorage device or in a propagated signal, for execution by, or tocontrol the operation of, data processing apparatus, e.g., aprogrammable processor, a computer, or multiple computers. A computerprogram, such as the computer program(s) described above, can be writtenin any form of programming language, including compiled or interpretedlanguages, and can be deployed in any form, including as a stand-aloneprogram or as a module, component, subroutine, or other unit suitablefor use in a computing environment. A computer program can be deployedto be executed on one computer or on multiple computers at one site ordistributed across multiple sites and interconnected by a communicationnetwork.

Method steps may be performed by one or more programmable processorsexecuting a computer program to perform functions by operating on inputdata and generating output. Method steps also may be performed by, andan apparatus may be implemented as, special purpose logic circuitry,e.g., an FPGA (field programmable gate array) or an ASIC(application-specific integrated circuit).

While certain features of the described implementations have beenillustrated as described herein, many modifications, substitutions,changes and equivalents will now occur to those skilled in the art.

What is claimed is:
 1. A method comprising: transmitting, from awireless node, a first data unit via a first channel of a firstfrequency band of a plurality of frequency bands; selecting a secondfrequency band of the plurality of frequency bands; performing a contexttransfer at the wireless node from the first frequency band to thesecond frequency band; transmitting, from the wireless node, a seconddata unit via a second channel of the second frequency band; andretransmitting, after performing the context transfer, the first dataunit via the second channel of the second frequency band, whereinretransmitting the first data unit via the second channel of the secondfrequency band is part of one of: an automatic repeat request (ARQ)process; a hybrid ARQ (HARQ) process in which data units are encodedusing an error-correction code and error-detection information isappended to the data unit before transmission or retransmission; a chasecombining HARQ process in which the first data unit is coded andretransmitted via the second channel of the second frequency band; andan incremental redundancy HARQ process in which the first data unittransmitted via the first channel of the first frequency band and theretransmitted first data unit retransmitted via the second channel ofthe second frequency band are encoded differently or coded usingdifferent coding rates and puncturing techniques.
 2. The method of claim1, wherein the first channel comprises one or more subcarriers withinthe first frequency band, and the second channel comprises one or moresubcarriers within the second frequency band.
 3. The method of claim 1,wherein the performing a context transfer comprises sending, from thewireless node, control information associated with the second frequencyband.
 4. The method of claim 1, wherein the control informationcomprises synchronization related information associated with the secondfrequency band.
 5. The method of claim 1, wherein the controlinformation comprises at least one of: a location of the secondfrequency band or a frequency shift between the first frequency band andthe second frequency band, or a frequency shift between the firstchannel of the first frequency band and the second channel of the secondfrequency band, and/or a location of a resource allocation table.
 6. Themethod of claim 1, wherein performing a context transfer comprisesreassigning data units and associated control data from the firstfrequency band to the second frequency band.
 7. The method of claim 1,wherein performing a context transfer comprises: transferring data unitsstored in a first data transmission queue associated with the firstfrequency band to a second data transmission queue associated with thesecond frequency band; and re-assigning control data associated with thefirst frequency band from the first frequency band to the secondfrequency band.
 8. The method of claim 1, wherein the performing acontext transfer comprises transferring or re-assigning data units andassociated control data that are assigned to a first resource schedulerassociated with the first frequency band to a second resource schedulerassociated with the second frequency band.
 9. An apparatus comprising: awireless transceiver; and a multi-band scheduler; the apparatus beingconfigured to: transmit a first data unit via a first channel of a firstfrequency band of a plurality of frequency bands; select a secondfrequency band of the plurality of frequency bands; perform a contexttransfer at from the first frequency band to the second frequency band;transmit a second data unit via a second channel of the second frequencyband; and retransmit, after performing the context transfer, the firstdata unit via the second channel of the second frequency band, whereinretransmitting the first data unit via the second channel of the secondfrequency band is part of one of: an automatic repeat request (ARQ)process; a hybrid ARQ (HARQ) process in which data units are encodedusing an error-correction code and error-detection information isappended to the data unit before transmission or retransmission; a chasecombining HARQ process in which the first data unit is coded andretransmitted via the second channel of the second frequency band; andan incremental redundancy HARQ process in which the first data unittransmitted via the first channel of the first frequency band and theretransmitted first data unit retransmitted via the second channel ofthe second frequency band are encoded differently or coded usingdifferent coding rates and puncturing techniques.
 10. The apparatus ofclaim 9, wherein the apparatus comprises one of: a wireless accesspoint, base station, or node B; a wireless relay node or relay station;and a wireless user terminal or mobile station.
 11. A method comprising:transmitting data via a first channel on a first frequency band of aplurality of frequency bands in a wireless network; detecting acondition relating to the first frequency band; reassigning at leastsome control data relating to the first frequency band to a secondfrequency band of the plurality of frequency bands; transferring datastored in data transmission queues associated with the first frequencyband to data transmission queues associated with the second frequencyband; transmitting the transferred data via the second frequency band;and sending, before the reassigning and transferring, a message to auser terminal requesting that the user terminal to synchronize with thesecond frequency band or prepare for a transfer to the second frequencyband.
 12. The method of claim 11, wherein the detected conditioncomprises determining that the first frequency band is unavailable dueto use or sharing with another operator or network.
 13. The method ofclaim 11, wherein the detected condition comprises one or more of thefollowing: determining or detecting one or more of: an unavailability ofat least a portion of the first frequency band for the flow; a networkcongestion or traffic load on at least a portion of the first frequencyband that exceeds a congestion threshold; a channel quality indicationfor at least a portion of the first frequency band that identifies achannel quality less than a channel quality threshold; and/or a Qualityof Service (QoS) for at least a portion of the first frequency band isless than a QoS required or requested by the flow.
 14. The method ofclaim 11, and further comprising: receiving a message from the userterminal via the first frequency band that includes estimated channelquality for the second frequency band; providing the channel qualityindication for the second frequency band to a resource schedulerassociated with the second frequency band.
 15. An apparatus for use in awireless node comprising: a wireless transceiver; a controller, theapparatus being configured to: transmit data via a first channel on afirst frequency band of a plurality of frequency bands in a wirelessnetwork; detecting a condition relating to the first frequency band;reassign at least some control data relating to the first frequency bandto a second frequency band of the plurality of frequency bands; transferdata stored in data transmission queues associated with the firstfrequency band to data transmission queues associated with the secondfrequency band; transmit the transferred data via the second frequencyband; and send, before the reassigning and transferring, a message to auser terminal requesting that the user terminal to synchronize with thesecond frequency band or prepare for a transfer to the second frequencyband.
 16. A method comprising: receiving one or more data units of afirst flow at a wireless node; assigning each received data unit of thefirst flow to a first frequency band of a plurality of frequency bands;receiving one or more data units of a second flow at a wireless node;assigning each received data unit of the second flow to a secondfrequency band of the plurality of frequency bands; determining a bandtransfer condition for the first flow; performing a context transferfrom the first frequency band to the second frequency band for the firstflow based on the determined band transfer condition; and furthercomprising: transmitting, before performing the context transfer, dataunits of the first flow via a first channel of the first frequency band;transmitting, after performing the context transfer, data units of thefirst flow via a second channel of the second frequency band; andtransmitting data units of the second flow via a third channel of thesecond frequency band.
 17. The method of claim 16, wherein theperforming a context transfer comprises assigning one or more of thedata units of the first flow, and associated control data, to the secondfrequency band.
 18. A multi-band scheduler for use in a wireless node,the multi-band scheduler configured to: receive one or more data unitsof a flow; assign each received data unit of the flow to a firstfrequency band of a plurality of frequency bands; determine a bandtransfer condition for the flow; and perform a context transfer from thefirst frequency band to a second frequency band for the flow based onthe determined band transfer condition, and further configured to:transmit, before performing the context transfer, data units of thefirst flow via a first channel of the first frequency band; transmit,after performing the context transfer, data units of the first flow viaa second channel of the second frequency band; and transmit data unitsof the second flow via a third channel of the second frequency band.